Private First Class Koch was a medic with the Medical Company, 21st Infantry Regiment, 24th Infantry Division. He was taken Prisoner of War while tending his wounded comrades in South Korea on 5 July 1950, forced to march to North Korea on the "Tiger Death March", and died as a prisoner at An-Dong, North Korea, on 3 May 1951 from malnutrition. His remains were not recovered. His name is inscribed on the Courts of the Missing at the Honolulu Memorial.

Koch was awarded, the Combat Medical Badge, the Prisoner of War Medal, the Korean Service Medal, the United Nations Service Medal, the National Defense Service Medal, the Korean Presidential Unit Citation and the Republic of Korea War Service Medal.